1. Technical Field
Various embodiments generally relate to a calibration circuit and a calibration apparatus including the same, and more particularly, to a calibration circuit for matching impedances and a calibration apparatus in which a plurality of calibration circuits sharing a resistor for impedance matching sequentially perform impedance calibrating is operations.
2. Related Art
Electronic devices may include a buffer or a driving circuit for input and output of data or signals from and to an exterior. Terminals for performing input and output are electrically coupled with transmission lines. Because an impedance difference occurs between an interior and an exterior, it is necessary to match the impedances of input and output terminals and the impedances of transmission lines.
An impedance mismatch may occur due to noise, a variation in a power supply voltage, a variation in an operating temperature, a variation in a manufacturing process, and so forth. If impedance matching is not accomplished, operational reliability may deteriorate since it is difficult to sense the precise values of input and output data or signals.